12640205655 has 128 divisors (see below), whose sum is σ = 28207872000. Its totient is φ = 5217177600.

The previous prime is 12640205647. The next prime is 12640205663. The reversal of 12640205655 is 55650204621.

12640205655 is a `hidden beast` number, since 1 + 2 + 640 + 2 + 0 + 5 + 6 + 5 + 5 = 666.

It is an interprime number because it is at equal distance from previous prime (12640205647) and next prime (12640205663).

It is not a de Polignac number, because 12640205655 - 2³ = 12640205647 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 1544775 + ... + 1552935.

It is an arithmetic number, because the mean of its divisors is an integer number (220374000).

Almost surely, 2^12640205655 is an apocalyptic number.

12640205655 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

12640205655 is an abundant number, since it is smaller than the sum of its proper divisors (15567666345).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

12640205655 is a wasteful number, since it uses less digits than its factorization.

12640205655 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8342 (or 8336 counting only the distinct ones).

The product of its (nonzero) digits is 72000, while the sum is 36.

The spelling of 12640205655 in words is "twelve billion, six hundred forty million, two hundred five thousand, six hundred fifty-five".